Extreme Macro Focusing Helicoid

If you've been trying out reverse lens macro then adding a focusing helicoid to your bag may give you a bit more versatility over the field of view that you get from your extreme macro shots.

Focusing Helicoid, shown fully extended on the right and fully compressed on the left.

Don't bother with super expensive branded ones, go for an eBay special as they're really well made and much better value for money.

Focusing helicoids are generally made in various mounts including M42: expect to pay about £50 on eBay. Great for field use: rather than carrying lots of bits about, carry just the one focusing helicoid and a few lenses and you should be covered nicely.

Focusing Helicoids are easy to source and are basically a variable extension tube. So rather than carrying lots of bits about, carry just the one focusing helicoid and a few lenses and you should be covered nicely.

What is a Focusing Helicoid?

A focusing helicoid is a metal lens-like device that has no glass inside and extends to about two, almost three times its own length.
So in other words, a 50mm focusing helicoid allows for an extension between 50mm not extended and about 90mm fully extended. Bottom line: similar to a bellows but without the accordion part, and similar to an extension tube that can actually be extended in use.

Varying the distance to a reversed lens will vary the magnification produced by that reversed lens, so it's a way to have 1:1 to 5:1 in your bag using as few bits as possible without having access to an all-in-one MPE-65.

You can buy focusing helicoid in various mount sizes and mounts from eBay sellers, and they tend to be very well made products.

Make sure that the end that the lens (reversed lens) sits on does not rotate, as that's quite difficult to deal with.

I use focusing helicoids to take enlarger lenses out in the field and give myself some variability over the magnification that they produce

eBay Focusing Helicoids

People like to diss Chinese products, but the focusing helicoid I've purchased through eBay is a superbly made piece of equipment.
The helicoid has just the right amount of oiling in it so that the movement is oiled but easy.

The helicoid does not cause deviation in the focus direction and the fit is snug. At 1/3 the price of brand offerings it's a good deal and an example of ripoff manufacturers being beaten at their own game by a company that's prepared to offer products on the market without the massive markup that photography seems to inspire. Power to them.

Focusing Helicoid Uses

I use focusing helicoids to take enlarger lenses out in the field and give myself some variability over the magnification that they produce. Between a three reasonable enlarger lenses, I have a range of 1:2 to 4:1 which is more than enough of a magnification range to be able to shoot almost everything I need to.

Focusing Helicoid Cost

The cost largely depends on the mount you're buying and the range you're after, but you're looking at £25-£75 to buy a focusing helicoid.

Branded Focusing Helicoids

Most of the big photography brands made a branded focusing helicoid at one time or another, but most of them are no longer available. For example the Pentax Helicoid Extension Tube B provided an infinitely stepless adjustment range from 26.5mm to 46.5mm but it is no longer available. Pentax actually made several including a PK model and a M42 model, and they do come up on eBay from time to time.

Nikon never made one and I am not personally aware of a specific Canon focusing helicoid. Leitz Wetzlar made a Leitz OTZFO universal focusing helicoid which together with a specific extension tube was designed to mount the optical head of the 135 F4 Hektor or the 135 f4.5 Elmar lenses on the Leitz Visoflex, and of course it is also perfectly possible to make your own helicoid by cannibalising an old lens and removing the glass, even keeping in the aperture to use as an empty lens.

Konica did a Auto Helicoid AR in the 1960s and 1970s, which can be adjusted by a turning ring in the range from 47.5 mm up to 69.5 mm, whilst Olympus did a very nice telescopic auto tube helicoid which went between 65 mm and 116 mm but which was discontinued in 2003.

Which Focusing Helicoid To Buy?

Focusing helicoids come in various ranges, ie 12mm-17mm, 25mm-55mm, 35mm-90mm so it is a bit unclear which might suit your purpose best. This generally depends on the mm of the lens that you're using and the magnification you want to get out of it, ie with a 35mm the 35-90 should get you a nice range of magnification (to about 3:1) and even more if you find some cheap M42 extensions to use as added length for added magnification. Do beware though that on some of the shorter lengths you'll have vignetting if you just use those without any other extension.

Comments (12)

What about using one in order to acheve, for example, the distance of an objective (ex. 210/0) must have from the sensor (substracting the 10 cm that the optical system of a microskope requires),that many of the objectives propose?

I would just like to point out that the Olympus OM telescopic tube can still be found on Ebay from time to time. I have two, one of each version. The versions matter only if you want the magnification scales for the later Olympus Macro lenses. The advantage is that each extension setting (continuously variable between minimum and maximum) can be locked, unlike helicoids which you can turn unintentionally, changing the extension. I have used mine with OM lenses and with these, and with other lenses, reversed. I have also used hybrid setups, incorporating e.g. both M42 and the OM tube. My Kiron OM mounts would also fit but I use other lens options now.

Mounting a normal reversed lens is no problem, but my fisheye doesn't have any filter rings so that couldn't be mounted. There are also many applications I have where I want to use a helicoid without reversing the lens. These include: Use with micro 4/3 where a helicoid built into the adapter can give increased focal range whilst still including infinity. Adding focus capability to my bellows lens. Using enlarger lenses for non macro applications (one of my enlarger lenses is apparently suitable for UV photography but is unweildy mounted via a bellows). Looking again on e-bay I've found a PK lens to nikon camera adapter and a nikon lens to m42 adapter that could be combined to give PK to M42 but I suspect the combination will add ~2cm to the opticsal path which is more than most of my uses can cope with. I will probably have to combine a m42 extension tube with a cheap PK one using a MDF disc & glue...

I've got a couple of M42 helicoids and would like to be able to mount PK lenses on them do you know a source of affordable adapters? Obviously it will involve an increase in the overall length, but using a slightly shorter helicoid should stop that being an issue. GRB can custom make them but want £85 to do it, and I can't keep throwing money at my hobby!